My old Taco 555-102 zone valve head shorted out the other day (upstairs zone) so I replaced it with the Taco 555-050RP. Taco says this is the correct replacement for 555. When I turn up the thermostat for this zone, the head gets warm, but the pipe to the baseboards is still cold (as well as the zone valve).
My system has 2 zones, so to make sure there wasnt something wrong with the zone valve, I swapped heads with the zone that I know works. So now I have heat in the upstairs zone, but not the downstairs zone and the new head stills gets warm, but the pipe is cold.
Did I just buy a bad head? Or is it not compatible? The zone valve head that works was replaced about 2 months ago by my boiler repair company. The one I bought looks almost identical to the one the company used (they are both the gold taco).